Loud-speaker having auxiliary equipment disposed therein



June 5, 1951 A. w. PAGE 2,555,365

LouDsPEI-IKER HAVING AUXILIARY EQUIPIIIEIIT nIsPosED THEREIN Filed oct. 12, 1949 |4 ATTORNEY Patented June 5, 1951 LOUD-SPEAKER HAVING AUXILIARY EQUIPMENT DISPOSED THEREIN Arthur W. Page, Red Bank, N. J.

Application October 12, 1949, Serial No. 121,046

2 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Goverment for governmental purposes, without the payment of any royalty thereon.

This invention relates to improvements in loudspeakers.

Associated with the conventional loudspeakers or Vloudspeaker driving units in radio or sound apparatus, are the auxiliary devices such as impedance-matching transformers, switches, electrical attenuators, and frequency-corrective networks. Heretofore in the engineering design, allowance has been made for the space required by each of these devices in the complete assembly. In the various prior constructions or assemblies, this has been necessary although lesser values of overall dimensions of the apparatus would have been preferred.

With the foregoing in mind, it is one of the objects of my invention to provide an improved construction or arrangement for loudspeakers or loudspeaker driving units wherein the same, and one or more of the auxiliary devices therefor, are related and cooperate so as to require substantially less space than would otherwise be required.

Other objects and advantages Will hereinafter appear.

For the purpose of illustrating my invention, an embodiment thereof is shown in the drawing, wherein Fig. 1 is an enlarged elevational View, partly diagrammatic and partly in sectiony of loudspeaker apparatus constructed and operating in accordance with my invention, the section being taken on the line I-I in Fig. 3;

Fig. 2 is a graphical illustration of the operating characteristics of my improved construction, as compared to that of a loudspeaker representative of the prior art constructions; and

Fig. 3 is a plan view, partly broken away, of one of the elements in Fig. 1.

In accordance with one aspect of my invention, an impedance-matching transformer is physically and integrally embodied within the magnetic structure of the loudspeakenthe arrangement being such that the laminated core and coils of this transformer replace the central polen piece of the prior constructions.

With reference to Fig. 1, the numeral I designates the conventional permanent magnet cup or housing of the transformer. Forming the base of cup III is a base plate 3 I, of magnetic material. To this cup is also secured a plate I I of magnetic material, this plate being provided with a central opening so that the inner, circular portion I2 thereof serves as one of the poles. The other pole is provided by the enlarged or mushroomshaped head I4 of a yoke or U-shaped, central polepiece I5 which is fixed to the base plate 3|. This polepiece may also be a casting of malleable iron or steel, and by virtue of its characteristic shape and disposition, constitutes an important feature and functions in several important ways in my improved construction. For example, an auxiliary device, such as a conventional impedance-matching transformer or inductance I6, having a laminated iron-core I3, may be housed in and fixed to the base plate 3|, between the legs Il of the polepiece I5.

The head I4 is centrally disposed in the central opening in plate II, to form a concentric and uniform air gap I8 within which a voicecoil I9 is disposed and free to move. Coil I9 is fixed to a cylindrical form 20, which in turn is fixed to the adjacent face of a diaphragm 2|. The diaphragm 2I may be secured to plate II by studs 22 which may also serve to secure plate I I to the cup or housing I0.

The magnetic circuit of my improved loudspeaker can be traced through plate II, the housing I0, the base plate 3|, the two legs I'I and the head I4 of yoke I5, and the air gap I8 defined by the respective adjacent and concentric pole faces of the yoke-head I4 and the plate I2.

By reason of my improved construction, the flexible leads or connections 23 between the voice coil I9 and the secondary winding of transformer I6, are not only relatively short, but they are internal and fully protected. Leads 24, 25, 26 and 21 from the primary winding of transformer I6, provide various desired impedance taps, and are brought out at the rear or base of the loudspeaker, as shown. There is thus provided a loudspeaker of standard impedance, or a matchingfl circuit to meet any special impedances. In Fig. 1, the taps 24 and 25 are shown connected to the G-ohm output line from a radio or audio system 28.

My improved construction is not only rugged and compact, but its resistance to breakage is substantially higher than that of the various constructions proposed heretofore. Furthermore, it lends itself readily and economically to mass production, and possible leakage of transformer flux is reduced to a minmum.

The improved operating action of my improved loudspeaker is shown by the test curves 29 and 30 in Fig. 2. Curve 29 is that of a loudspeaker of my improved design, with the internal transformer I6. Curve 30 is that of a loudspeaker of substantially the same size and having an external transformer, as heretofore.

For the purpose of illustration, the embodiment of my invention shown in Fig. 1 includes the impedance-matching transformer or inductance I6. It Will be understood, however, that one or more of the usual auxiliary devices such as electrical Y attenuators, switches, and frequency-corrective networks, may be housed within the loudspeaker structure, between the legs l1 of the yoke or central polepiece I5. Y

Details of construction and arrangement which are conventional and well known to those skilled in the art, have been omitted from the present disclosure for the purpose of simplication. Examples of such details are disclosed in Patent No. 2,371,951 issued March 20, 1945 toEllsworth D. Cook, and in Patent No. 1,750,009 issued March 11, 1930 to Karl K. Jensen.

It will be understood that various modiications, such as in the size, shape and arrangement of the parts, are possible Without departing from the spirit of my invention or the scope of the claims.

What is claimed is:

1. In a loudspeaker, a substantially cup-shape housing member forming a magnet, a plate of magnetic material fixed to said member and provided with a central opening, a yoke disposed within and fixed to the bottom of said member, an extension of said yoke being disposed within and centrally of said opening to form an air gap, a diaphragm, a voice coil xed with respect to said diaphragm and disposed within said air gap,

auxiliary coupling means disposed within the U-conguration of said polepiece and iixed to the bottom of said member, and means disposed entirely within said member and connecting said voice coil directly to said means.

2. In a loudspeaker, a substantially cup-shape housing member forming a magnet, a plate of magnetic material xed to said member and provided With a central opening, a yoke disposed Within said member, the two legs of the U-shape form of said polepiece being xed to the bottom of said member, an extension of said yoke being disposed Within and centrally of said opening to form an air gap, a diaphragm xed to and supported by said plate, a voice coil xed with respect to said diaphragm and disposed within said air gap, a transformer havingr a secondary winding and disposed between said legs and xed to the bottom of said member, and flexible connections disposed entirely within said member and connecting said voice coil directly to said Winding.

ARTHUR W. PAGE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,632,332 Hayes June 14, 1927 1,774,855 Titcomb Sept. 2, 1930 1,923,831 Juhasz Aug. 22, 1933 2,478,042 Root Aug. 9, 1949 2,492,255 Anghern Dec. 27, 1949 

